We must bear in mind that the truth is never clear. If it was, no one would ever disagree with us.
We must bear in mind that the more ignorant a person is of a subject, the more receptive he will be to our advice. Every time a person asks a question he has recognised his own ignorance, so it is a commonplace occurrence for a person to know he doesn't know everything.
We must bear in mind that pessimism and defeatism never solve problems, so it is better to be optimistic about whether a person can or will be persuaded of a good idea.
We must not be scared to disagree. People disagree all the time. But this does not make them hurt each other. It is not necessary to force agreement from a child, or worry overly about what he believes. That is his choice.
We should keep a sense of perspective. The worst that could happen is frequently better than the price of intervening.
We must stop thinking of all situations as the parent choosing what will happen. That is the model of a benevolent dictator. And one of the flaws is the enormous pressure and responsibility it puts on the *parent*.